November 18, 2008

Drilling 5 (Rotating ..)

The main function of rotating system is to transmit power to rotate drill string and give burden to drilling string above the bit.
Rotating system consisted of Four sub-component :
(1) rotary assembly (2). drill string (3). The Bit. (4) Specialized Down hole tools

Rotating system has function for :
Rotate drill string during drilling operation.
Suspend drill string by slip that attached at rotary table when jointed or release parts/joint of
drill pipe .
Rotating System

1. Rotary Assembly
Rotary table
Master Bushing
Kelly Bushing
Rotary Slips
2. Drill String :
Drill Pipe (DP)
Drill Collar (DC)

3. The Bit :
Drag Bit
Rock Bit (Roller-Cone Bit)
Diamond Bit.

4. Specialized Down Hole Tools :

Rotary Reamer
Shock Absorber

Rotary Table :

Generate power to rotate drill string through kelly bushing and kelly. Detaining drill pipe in hole when make up or release drill pipe. Speed of rotary table controlled by a driller with handle that exist in draw work ( driller console).
Rotary Table located in floor of rig beneath crown block and precisely the above hole. Work with master bushing, kelly bushing to rotate kelly and drill pipe network.

Rotary Slip :

As Holder drill pipe at joining or release of section of drill string.

Work Mechanism :
When make up and releasing the pipe, the slip inserted into master bushing at rotary table in order to the pipe not fall when jointed or released.

Drill Pipe :

Connecting kelly to drill collar and the bit.
Giving long of length to penetrate to the deeper formation
Allow to travel up and down of the bit.
Transmit rotation from rotary table.
To circulate the drilling mud from swivel to the bit..

Basic Type :
Standard is used from the surface to the top of drill collars. The normal arrangement is drill pipe followed by drill collars above the bit.
Heavy-Weight DP (HWDP) is used in special situation in place of drill collars where differential wall sticking and other down hole problems are encounter

Stand :
•Drill pipe joint are usually connected and disconnected from the drill stem in section. This section are called “stands”. The Number of joints in a stand is determined by rig height and whether range 2 or range 3 DP is used.
Drill Colar

Giving weight on bit / WOB > 3 ton), so allow drill string in tension when drilling operation to keep hole straight (dog leg).
Making rotation of Drill string stable (2-60 DC).
Strengthen underside from of drill string in order to able to detain torsion


The Bit Type :
The Drag Type Bit
The Rolling Cone or “Rock” Bit
The Fixed Cutter (Head) Bit

Stabilizers are used in the “bottom hole assembly” to stabilize the bit and drill collars in the hole during drilling operations.

Improving penetration
Minimize possibility of broken (fatigue) to drill collar.
Prevent pipe sticking

Shock Absorber

Shock Absorber placed underside of installation of drill collar to absorb vibrations and every shock load which possible happened when crushing the formation by the bit once drill interspersed (intermittent) hard and soft formation, so it reduce the possibility of damage of drill stem and the rig.

•Primary function Sock Absorber are to reduce :

(1) drill collar and drill pipe connection fatigue and failure,

(2) Shock loads on the bit, protecting teeth and bearings.

continue ...

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